Refresh data used in Shiny app via web browser

I'm new to Shiny and have made a simple app in which I have a spreadsheet stored in the app's directory. The app imports the spreadsheet and summarises the data contained in the spreadsheet. The data in the spreadsheet is updated regularly, and each time the data in the spreadsheet is updated, I want the Shiny app to update. Is there a way I can use a web browser to update the Shiny app, rather than having to go into RStudio and re-deploy the app?

I think you are asking how to upload a file interactively
Shiny - File Upload Control — fileInput (rstudio.com)

That allows me to choose a file, but once I have chosen it, the app does not update.

Also, is there a way to update the app without having to choose a file each time?

indeed its not magic, you will need to program it what to do with the file that is uploaded and put in the temporrary directory. i.e. you can read it and use it in your app.

If the file has a constant name, and is already in a local file system of the app's runtime; then yes, you can do a simple reactive poll to regularly check it for changes, and you can write logic for what to do when it changes, such as reload from it.